Other than that try to network with house flippers in your area, you may be able to get a ballpark of what they're spending per sq foot, as long as you understand this will be just a preliminary number to see if the house is worth checking out further. 

On ARV in Knoxville I would say between $100-$130 a square foot is pretty typical.

If it was a normal tub/shower combo it would take up a foot LESS of space too.Our question is: Would we decrease the value of the house by getting rid of the expensive tile and jacuzzi and replacing it with a normal tub/shower that’s more in style and less dangerous to get into?

One of the comps they used is outside of what I would consider to be the relevant geographic district and it was significantly lower per square foot.

From personal experience, you could wake up swimming in a foot of water! 

I am considering purchasing a 12k sq foot building with architectural plans  already in place to convert to 12-14 condos.

Also, check out the financials for the association and make sure they are on solid footing. 

In May 2015, I bought an empty lot in Stockton, CA, a 12,000 square foot empty land parcel.

It has four 1500 square foot apartments, each with 1 bed and 1 bath.

It has four 1500 square foot apartments, each 1B/1b.